Reduce? The larger the corporation, the larger the overhead introduced, and less efficient it becomes for intellectual work. Your thinking only applies to manufacturing.
Well, note that the size of Think Tanks is a lot smaller than the auto companies. However, there are still some things to be gained from the pool of talent at Valve. Gearing up a new team doesn't involve hiring. There's no paperwork. There's a lot of communicating (a good thing) and moving some desks.
